Webon june 23, 1992, mafia boss john gotti, who was nicknamed the “teflon don” after escaping unscathed from several trials during the 1980s, is sentenced to life. Webgotti was sentenced to life in prison without the possibility of parole, marking the end of his reign as the boss of the gambino family. The conviction was a significant. Weba jury in new york finds mobster john gotti, nicknamed the teflon don for his ability to elude conviction, guilty on 13 counts, including murder and racketeering.